I got this error message while running my app from within Xcode and the Archived exported app do NOT execute under macOS 10.14
[default] Unable to load Info.
Possibly not relevant but I had a similar issue today - XCode 10 + High Sierra.
Mine was an issue with the Fabric/Run script in the Build Phases window. The error suggested it was a 'timing' issue. I checked the box that said 'Run script only when installing' in the build phases window, and now my project builds and runs again.
[UPDATE] My solution was found here: XCode 10 archive failure